Patients with severe respiratory diseases such as chronic obstructive pulmonary disease (COPD) or obesity-hypoventilation syndrome (OHS) can benefit from having non-invasive ventilation (NIV). NIV consists of a machine (ventilator) that is blowing air inside a patient's airway through a mask. NIV provides patients with a bigger breath. Bigger breaths help patients to have a more oxygen and less waste gas (or carbon dioxide) in their body.